diff options
Diffstat (limited to 'net/ipv4/inet_connection_sock.c')
-rw-r--r-- | net/ipv4/inet_connection_sock.c | 214 |
1 files changed, 214 insertions, 0 deletions
diff --git a/net/ipv4/inet_connection_sock.c b/net/ipv4/inet_connection_sock.c index 136ada050b63..026630a15ea0 100644 --- a/net/ipv4/inet_connection_sock.c +++ b/net/ipv4/inet_connection_sock.c @@ -23,6 +23,7 @@ #include <net/ip.h> #include <net/route.h> #include <net/tcp_states.h> +#include <net/xfrm.h> #ifdef INET_CSK_DEBUG const char inet_csk_timer_bug_msg[] = "inet_csk BUG: unknown timer value\n"; @@ -398,8 +399,100 @@ void inet_csk_reqsk_queue_hash_add(struct sock *sk, struct request_sock *req, inet_csk_reqsk_queue_added(sk, timeout); } +/* Only thing we need from tcp.h */ +extern int sysctl_tcp_synack_retries; + EXPORT_SYMBOL_GPL(inet_csk_reqsk_queue_hash_add); +void inet_csk_reqsk_queue_prune(struct sock *parent, + const unsigned long interval, + const unsigned long timeout, + const unsigned long max_rto) +{ + struct inet_connection_sock *icsk = inet_csk(parent); + struct request_sock_queue *queue = &icsk->icsk_accept_queue; + struct listen_sock *lopt = queue->listen_opt; + int max_retries = icsk->icsk_syn_retries ? : sysctl_tcp_synack_retries; + int thresh = max_retries; + unsigned long now = jiffies; + struct request_sock **reqp, *req; + int i, budget; + + if (lopt == NULL || lopt->qlen == 0) + return; + + /* Normally all the openreqs are young and become mature + * (i.e. converted to established socket) for first timeout. + * If synack was not acknowledged for 3 seconds, it means + * one of the following things: synack was lost, ack was lost, + * rtt is high or nobody planned to ack (i.e. synflood). + * When server is a bit loaded, queue is populated with old + * open requests, reducing effective size of queue. + * When server is well loaded, queue size reduces to zero + * after several minutes of work. It is not synflood, + * it is normal operation. The solution is pruning + * too old entries overriding normal timeout, when + * situation becomes dangerous. + * + * Essentially, we reserve half of room for young + * embrions; and abort old ones without pity, if old + * ones are about to clog our table. + */ + if (lopt->qlen>>(lopt->max_qlen_log-1)) { + int young = (lopt->qlen_young<<1); + + while (thresh > 2) { + if (lopt->qlen < young) + break; + thresh--; + young <<= 1; + } + } + + if (queue->rskq_defer_accept) + max_retries = queue->rskq_defer_accept; + + budget = 2 * (lopt->nr_table_entries / (timeout / interval)); + i = lopt->clock_hand; + + do { + reqp=&lopt->syn_table[i]; + while ((req = *reqp) != NULL) { + if (time_after_eq(now, req->expires)) { + if ((req->retrans < thresh || + (inet_rsk(req)->acked && req->retrans < max_retries)) + && !req->rsk_ops->rtx_syn_ack(parent, req, NULL)) { + unsigned long timeo; + + if (req->retrans++ == 0) + lopt->qlen_young--; + timeo = min((timeout << req->retrans), max_rto); + req->expires = now + timeo; + reqp = &req->dl_next; + continue; + } + + /* Drop this request */ + inet_csk_reqsk_queue_unlink(parent, req, reqp); + reqsk_queue_removed(queue, req); + reqsk_free(req); + continue; + } + reqp = &req->dl_next; + } + + i = (i + 1) & (lopt->nr_table_entries - 1); + + } while (--budget > 0); + + lopt->clock_hand = i; + + if (lopt->qlen) + inet_csk_reset_keepalive_timer(parent, interval); +} + +EXPORT_SYMBOL_GPL(inet_csk_reqsk_queue_prune); + struct sock *inet_csk_clone(struct sock *sk, const struct request_sock *req, const unsigned int __nocast priority) { @@ -424,3 +517,124 @@ struct sock *inet_csk_clone(struct sock *sk, const struct request_sock *req, } EXPORT_SYMBOL_GPL(inet_csk_clone); + +/* + * At this point, there should be no process reference to this + * socket, and thus no user references at all. Therefore we + * can assume the socket waitqueue is inactive and nobody will + * try to jump onto it. + */ +void inet_csk_destroy_sock(struct sock *sk) +{ + BUG_TRAP(sk->sk_state == TCP_CLOSE); + BUG_TRAP(sock_flag(sk, SOCK_DEAD)); + + /* It cannot be in hash table! */ + BUG_TRAP(sk_unhashed(sk)); + + /* If it has not 0 inet_sk(sk)->num, it must be bound */ + BUG_TRAP(!inet_sk(sk)->num || inet_csk(sk)->icsk_bind_hash); + + sk->sk_prot->destroy(sk); + + sk_stream_kill_queues(sk); + + xfrm_sk_free_policy(sk); + + sk_refcnt_debug_release(sk); + + atomic_dec(sk->sk_prot->orphan_count); + sock_put(sk); +} + +EXPORT_SYMBOL(inet_csk_destroy_sock); + +int inet_csk_listen_start(struct sock *sk, const int nr_table_entries) +{ + struct inet_sock *inet = inet_sk(sk); + struct inet_connection_sock *icsk = inet_csk(sk); + int rc = reqsk_queue_alloc(&icsk->icsk_accept_queue, nr_table_entries); + + if (rc != 0) + return rc; + + sk->sk_max_ack_backlog = 0; + sk->sk_ack_backlog = 0; + inet_csk_delack_init(sk); + + /* There is race window here: we announce ourselves listening, + * but this transition is still not validated by get_port(). + * It is OK, because this socket enters to hash table only + * after validation is complete. + */ + sk->sk_state = TCP_LISTEN; + if (!sk->sk_prot->get_port(sk, inet->num)) { + inet->sport = htons(inet->num); + + sk_dst_reset(sk); + sk->sk_prot->hash(sk); + + return 0; + } + + sk->sk_state = TCP_CLOSE; + __reqsk_queue_destroy(&icsk->icsk_accept_queue); + return -EADDRINUSE; +} + +EXPORT_SYMBOL_GPL(inet_csk_listen_start); + +/* + * This routine closes sockets which have been at least partially + * opened, but not yet accepted. + */ +void inet_csk_listen_stop(struct sock *sk) +{ + struct inet_connection_sock *icsk = inet_csk(sk); + struct request_sock *acc_req; + struct request_sock *req; + + inet_csk_delete_keepalive_timer(sk); + + /* make all the listen_opt local to us */ + acc_req = reqsk_queue_yank_acceptq(&icsk->icsk_accept_queue); + + /* Following specs, it would be better either to send FIN + * (and enter FIN-WAIT-1, it is normal close) + * or to send active reset (abort). + * Certainly, it is pretty dangerous while synflood, but it is + * bad justification for our negligence 8) + * To be honest, we are not able to make either + * of the variants now. --ANK + */ + reqsk_queue_destroy(&icsk->icsk_accept_queue); + + while ((req = acc_req) != NULL) { + struct sock *child = req->sk; + + acc_req = req->dl_next; + + local_bh_disable(); + bh_lock_sock(child); + BUG_TRAP(!sock_owned_by_user(child)); + sock_hold(child); + + sk->sk_prot->disconnect(child, O_NONBLOCK); + + sock_orphan(child); + + atomic_inc(sk->sk_prot->orphan_count); + + inet_csk_destroy_sock(child); + + bh_unlock_sock(child); + local_bh_enable(); + sock_put(child); + + sk_acceptq_removed(sk); + __reqsk_free(req); + } + BUG_TRAP(!sk->sk_ack_backlog); +} + +EXPORT_SYMBOL_GPL(inet_csk_listen_stop); |